This message appears when trying to run AnswerBook on a generic X11 window server or on a generic X terminal.
Running AnswerBook requires Display PostScript (DPS), or a NeWS server, or the Adobe DPS NS remote display software. Additionally, a complete LaserWriter II Type-1 font set (including Palatino) should be installed on the X server. To find out if the X server has DPS, run xdpyinfo(1) to verify the presence of an "Adobe-DPS-Extension" line. X servers without this line do not know about DPS.